The Ethnologue as an academic book, is somewhat of a straw man in linguistics. Many people who write grants for language documentation projects (generally on under described or endangered languages) will cite the Ethnologue and some other resources or lack of resources . These efforts seeking funding are usually an effort to get more language data. The rationale for this is two fold:

Because so little is known that we do not know if the Ethnologue is correct.

Because there is a conflict between other published sources and the Ethnologue .